1. Field of the Invention
The present invention relates to swimming pool systems and, more specifically, to controlling the proportion of suction between a skimmer and a pool cleaner.
2. Description of the Related Art
As illustrated in FIG. 1 (not to scale), a swimming pool filtration system for an in-ground pool 10 typically includes a pump 12, a filter unit 14, and one or more skimmers 16. Skimmer 16 is located in the wall of pool 10 approximately at the average waterline 18. Skimmer 16 essentially comprises a box 20 that typically has a hinged flap or weir 22 that opens to admit water. Skimmer 16 is connected to filter unit 14 and pump 12 via a suction line 24. The water is pumped through filter unit 14 and returned to pool 10 via one or more return lines 26. An equalizer line 25 connects skimmer 16 to the main drain 27 of pool 10 and provides water to skimmer 16 to equalize pressure and prevent pump 12 from running dry in the event skimmer 16 becomes clogged. Leaves or other debris floating on the surface of the water are sucked into skimmer 16 and captured by a strainer basket (not shown) or filter unit 14.
A robotic cleaner 28 may also be included in certain pool filter systems. Cleaner 28 is a device that moves along the pool bottom and vacuums debris. Cleaner 28 can be connected to a coupling 29 in the wall of pool 10, which is in turn connected to pump 12 via a secondary suction line 30 that is coupled to (primary) suction line 24 at a junction valve box 32. A user can connect cleaner 28 to coupling 29 when the user desires to operate cleaner 28 and disconnect cleaner 28 from coupling 29 at other times, such as when swimmers are using the pool. Junction valve box 32 is typically located nearer pump 12 than pool 10. Junction valve box 32 is typically embedded in the concrete deck 34 that surrounds pool 10. Junction valve box 32 has a lid that can be removed to access its interior. Inside junction valve box 32 is a two-way valve (not shown) that proportionally controls the flow from skimmer 16 to pump 12 in relation to the flow from cleaner 28 to pump 12. In other words, if the valve is in one of its two extreme positions, it completely closes the path between cleaner 28 and pump 12 and completely opens the path between skimmer 16 and pump 12. Thus, pump 12 applies suction only to skimmer 16. If the valve is in the other of its two extreme positions, it completely opens the path between cleaner 28 and pump 12 and completely closes the path between skimmer 16 and pump 12. Thus, pump 12 applies suction only to cleaner 28. If the valve is in a mid-position, halfway between its two extreme positions, cleaner 28 and skimmer 16 experience equal suction from pump 12.
The inclusion of cleaner 28 in the filter system substantially increases the cost of pool construction because the installation of valve boxes and underground pipe runs are significant components of the cost. The pool construction company must install secondary suction line 30 that extends between coupling 29 and junction valve box 32, a distance that may exceed 50 or 100 feet in some pool systems. Furthermore, it is typically inconvenient for a pool owner or maintenance personnel to operate the valve while setting up cleaner 28 because junction valve box 32 is located relatively far from pool 10.
In addition, cement contractors have been known on occasion to inadvertently cement-over junction valve box 32 when pouring the cement for deck 34. Rather than engage in an uneconomical remediation procedure involving sawing through the concrete, repairing (or replacing) valve box 32, and patching up the cement work, if by good fortune or foresight the valve was in its mid-position or thereabout at the time junction valve box 32 was cemented over, the pool construction company may cleverly mitigate the cement contractor's error by leaving valve box 32 in its cemented-over state and placing a flow restrictor in the intake of skimmer 16 where it is coupled to suction line 30. The restrictor typically consists of a plug having a number of holes drilled in it that achieves a desired suction balance between skimmer 16 and cleaner 28. Typically, the intake of a skimmer 16 is already internally threaded to enable a plug to be screwed into it to facilitate pressure testing of the filter system. Thus, the pool construction company, in mitigating a cement contractor's error by this method, may simply screw such a plug into the intake and drill a number of holes through it until the total available suction created by pump 12 is divided in a selected proportion between skimmer 16 and secondary suction line 30. The greater the number of holes, the lesser the proportion of the suction that is diverted to secondary suction line 30.
It would be desirable to provide an improved system for controlling the proportion of suction between a skimmer and a pool cleaner that is economical to install and convenient to use. These needs are satisfied by the present invention in the manner described below.